Polyethyleneimine-modified resins effectively remove porcine circovirus and cellular prion protein

Polyethyleneimine (PEI) possesses various molecular weights (MWs), structures, and virus capture capacities. However, whether PEI can capture porcine circovirus (PCV) and animal cell-derived prion protein (PrP^C) that may contaminate source materials is unclear. Therefore, we conducted a feasibility study to assess the effectiveness of PEI in removing PCV and PrP^C as a model of pathogenic prions. The removal performance of PCV was evaluated by quantitative PCR using PEIs with various MWs, structures, and ion exchange capacities in Tris (pH 7.5) and acetate (pH 5.5) buffers under neutral (pH 7.5) to acidic (pH 5.5) conditions. Removal performances of PrP^C were also evaluated by western blotting using PEIs with various MWs and structures. Tris buffer did not affect the ability of PEI-modified resins to remove PCV, whereas acetate buffer affected removal performances, except those of PEI-10K-Br and PEI-70K-Br, which showed high ion-exchange capacities. PrP^C was captured by PEIs with high MWs, especially PEI-70K-Br, which was the most effective. The results of this feasibility study suggested that PEI-modified resin could remove PCV and PrP^C. PEI-70K-Br with an ion-exchange capacity of at least 0.3 meq/mL appears suitable as a PEI molecule for pathogen capture or removal of PCV or PrP^C from biological materials.